Is a VISA needed for a Canadian cruising from Shanghai to Japan and back before flying on to Vietnm?

My son planned to visit his brother on a cruise from Shanghai to Japan and back. It's a 4-day cruise and his time in China (including cruise) would be completed in under 6 days. Once back to Shanghai he has a flight booked to Vietnam. Everything he has read indicates no need for an entry permit since his trip is under 144 hours and he goes to another country from China. There is some confusion from the ship indicating that an entry permit may be necessary (maybe a standard link they send to all cruise passengers?). It's now too late for him to get an entry permit as he flies out tomorrow. Will he be ok?